Roller blinds (or roller shades) are commonly used on windows, doors and other structures for aesthetic purposes and for noise and light control. Most roller blinds are constructed with a clutch mechanism that allows the blind fabric or material to be raised or lowered as desired. Most commonly, roller blinds are activated through a looped cord or chain, that when pulled in one direction results in blind fabric being unrolled from the blind roller while pulling in an opposite direction results in blind fabric being rolled back onto the roller. The cord or chain typically engages a clutch mechanism, which in turn drives the roller in one direction or the other. While such structures have met with a considerable amount of success and have been widely used in both commercial and residential applications, they can at times present unsightly elongate loops of cord or chain that hang downwardly from the upper end of the roller. In some instances a guide or tensioning wheel may be mounted to the structure adjacent to the blind in order to hold the cord or chain neatly in place. However, the mounting of such guides or tensioning wheels increases the labour involved in mounting a roller blind to a structure and often results in a necessity to drill holes and screw or otherwise fasten the guide or tensioning wheel in place. In addition to the aesthetic and cost aspects associated with the use of lengthy cords or chains, in some instances the relatively long looping cords or chains have been found to present strangulation hazards when used in areas frequented by small children and infants. The threat of potential strangulation has caused some jurisdictions to mandate the use of guides or tensioning rollers to help reduce the possibility of the chains or cords becoming wrapped around the neck of an infant or small child, particularly when the roller blind is used in a child's bedroom or nursery.
To address such problems, others (for example see US Patent Publication No. U2009/0308547, dated Dec. 17, 2009) have proposed the use of a clutch mechanism having a single, retractable cord. Such clutches avoid the use of long looping cords or chains. However, to date their structures have exhibited a tendency to cause wear on internal components and to be relatively noisy on account of the general use of a ratcheting-type clutch.